1. Field of the Invention
This invention relates to a power semiconductor device, a method for manufacturing the same, and a method for driving the same, and more particularly to a power semiconductor device having a plurality of gate electrodes on a semiconductor substrate, a method for manufacturing the same, and a method for driving the same.
2. Background Art
The IGBT (Insulated Gate Bipolar Transistor) is widely used as a semiconductor switch in inverter circuits for industrial and automobile motors, power supplies for high-capacity servers, and UPSs (Uninterruptible Power Supplies). The IGBT is mainly used in applications working with a relatively large current from several hundred kilowatts to several megawatts. Planar gate IGBTs are conventionally used, but recently, vertical IGBTs based on trench gates are coming into use (see, e.g., JP 11-274484A).
There is a demand for larger current capacity in such IGBTs used for semiconductor switches, leaving room for improvement in this connection.